Tumor necrosis factor alpha, (TNF-α) is a cytokine that is released primarily by mono-nuclear phagocytes in response to immunostimulators. TNF-α is capable of enhancing most cellular processes, such as differentiation, recruitment, proliferation, and proteolytic degradation. At low levels, TNF-α confers protection against infective agents, tumors, and tissue damage. But TNF-α also has role in many disease processes. When administered to mammals or humans, TNF-α causes or aggravates inflammation, fever, cardiovascular effects, hemorrhage, coagulation, and acute phase responses similar to those seen during acute infections and shock states. Enhanced or unregulated TNF-α production has been implicated in a number of diseases and medical conditions, for example, cancers, such as solid tumors and blood-born tumors; heart disease, such as congestive heart failure; and viral, genetic, inflammatory, allergic, and autoimmune diseases.
The interleukins are a subclass of the cytokine family and possess a wide spectrum of biological activities including involvement in cell activation, cell differentiation, cell proliferation, and cell-to-cell interactions. Interleukin 1 beta (IL-1β) and interleukin 10 (IL-10), in combination with other cytokines, play a central role in mediating inflammatory processes and IL-1β has been implicated as both a growth factor and growth suppressor in certain tumor cells.
T-cells are a class of white blood cells that play an important role in the immune response, and help protect the body from viral and bacterial infections. Diminished T-cell levels strongly contribute to the inability of HIV patients to combat infections, and abnormally low T-cell levels are prominent in a number of other immune deficiency syndromes, including DiGeorge Syndrome, and in certain forms of cancer, such as T-cell lymphoma.
Cancer is a particularly devastating disease, and increase in blood TNF-α levels are implicated in the risk of and the spreading of cancer. Normally, in healthy subjects, cancer cells fail to survive in the circulatory system, one of the reasons being that the lining of blood vessels acts as a barrier to tumor-cell extravasation. But increased levels of cytokines, have been shown to substantially increase the adhesion of cancer cells to endothelium in vitro. One explanation is that cytokines, such as TNF-α stimulate the biosynthesis and expression of a cell surface receptors called ELAM-1 (endothelial leukocyte adhesion molecule). ELAM-1 is a member of a family of calcium-dependent cell adhesion receptors, known as LEC-CAMs, which includes LECAM-1 and GMP-140. During an inflammatory response, ELAM-1 on endothelial cells functions as a “homing receptor” for leukocytes. Recently, ELAM-1 on endothelial cells was shown to mediate the increased adhesion of colon cancer cells to endothelium treated with cytokines (Rice et al., 1989, Science 246:1303-1306). It has been suggested that an uncontrolled synthesis of IL-1β in leukemia blast cells is thought to result in the production of factors which promote proliferation of these malignant cells (Hestdal et al., 1992, Blood 80: 2486-94). In addition to this, IL-1β, in combination with other cytokines, appears to stimulate the growth of human gastric and thyroid carcinoma cells (Ito et. al., 1993, Cancer Research 53: 4102-6).
Inflammatory diseases such as arthritis, related arthritic conditions (e.g. osteoarthritis and rheumatoid arthritis), inflammatory bowel disease, sepsis, psoriasis, and chronic inflammatory pulmonary diseases are also prevalent and problematic ailments. Both TNF-α and IL-1β play central roles in the inflammatory response and the administration of their antagonists block chronic and acute responses in animal models of inflammatory disease. Conversely, IL-10 is an anti-inflammatory cytokine and is responsible for down-regulating inflammatory responses and as such possesses anti-inflammatory ability, including the suppression of production of proinflammatory cytokines such as TNF-α and IL-1β.
Heart disease has caused wide-spread death and debilitation. TNF-α has been implicated in a broad variety of cardiac pathophysiological conditions, such as septic shock, acute viral myocarditis, cardiac allograft rejection, myocardial infarction, and congestive heart failure (see e.g., Steadman et al., 1988, IEEE Trans. Biomed. Eng. 35:264-272; Tracey et al., 1986, Science Wash. DC 234:470-474; for a review see Ferrari, 1998, Cardiovascular Research 37:554-559). In one study, it was found that protective TNF-α binding proteins are downregulated in the hearts of patients with advanced congestive heart failure. During the study it was found that a large percentage of the diseased hearts analyzed had elevated TNF-α levels. The authors noted that the results support the proposition that the heart itself is a target of TNF-α and that myocardial TNF-α production may be a maladaptive mechanism that contributes to progressive heart failure (Torre-Amione et al., 1996, Circulation 93:704-711). In other studies, it has been demonstrated in-vitro and in-vivo (feline) that TNF-α is produced in the myocardium portion of the heart upon endotoxin stimulation. These studies provide compelling evidence indicating that a pathogenic level of biologically active TNF-α may be produced in the heart during endotoxin-mediated septic shock. And that such local concentrations of TNF-α may be the primary instigator of myocardial-function depression during systemic sepsis (Kapadia et al., 1995, J. Clin. Invest. 96:1042-1052). Thus, inhibitors of TNF-α activity may prevent its deleterious effects on the heart. For example, it has been demonstrated that soluble TNF-binding proteins modulate the negative inotropic effects of TNF-α in vitro in isolated contracting cardiac myocytes (Kapadia et al., 1995, Am. J. Physiol. 268:H517-H525).
Enhanced or unregulated TNF-α production has been implicated in viral, genetic, inflammatory, allergic, and autoimmune diseases, for example, HIV; hepatitis; adult respiratory distress syndrome; bone-resorption diseases; chronic pulmonary inflammatory diseases; dermatitis; cystic fibrosis; septic shock; sepsis; endotoxic shock; hemodynamic shock; sepsis syndrome; post ischemic reperfusion injury; meningitis; psoriasis; fibrotic disease; cachexia; graft rejection; auto-immune disease; rheumatoid spondylitis; arthritic conditions, such as rheumatoid arthritis and osteoarthritis; osteoporosis, Crohn's disease; ulcerative colitis; inflammatory-bowel disease; multiple sclerosis; systemic lupus erythrematosus; ENL in leprosy; radiation damage; asthma; and hyperoxic alveolar injury. For discussions see Tracey et al., 1987, Nature 330:662-664 and Hinshaw et al., 1990, Circ. Shock 30:279-292 (endotoxic shock); Dezube et al., 1990, Lancet. 335:662 (cachexia); Millar et al., 1989, Lancet 2:712-714 and Ferrai-Baliviera et al., 1989, Arch. Surg. 124:1400-1405 (adult respiratory distress syndrome); Bertolini et al., 1986, Nature 319:516-518, Johnson et al., 1989, Endocrinology 124:1424-1427, Holler et al., 1990, Blood 75:1011-1016, and Grau et al., 1989, N. Engl. J. Med. 320:1586-1591 (bone resorption diseases); Pignet et al., 1990, Nature, 344:245-247, Bissonnette et al., 1989, Inflammation 13:329-339 and Baughman et al., 1990, J. Lab. Clin. Med. 115:36-42 (chronic pulmonary inflammatory diseases); Elliot et al., 1995, Int. J. Pharmac. 17:141-145 (rheumatoid arthritis); von Dullemen et al., 1995, Gastroenterology, 109:129-135 (Crohn's disease); Duh et al., 1989, Proc. Nat. Acad. Sci. 86:5974-5978, Poll et al., 1990, Proc. Nat. Acad. Sci. 87:782-785, Monto et al., 1990, Blood 79:2670, Clouse et al., 1989, J. Immunol 142, 431-438, Poll et al., 1992, AIDS Res. Hum. Retrovirus, 191-197, Poli et al. 1990, Proc. Nail. Acad. Sci. 87:782-784, Folks et al., 1989, PNAS 86:2365-2368 (HIV and opportunistic infections resulting from HIV).
Pharmaceutical compounds that can block the activity or inhibit the production of certain cytokines, including TNF-α and IL-1β, may be beneficial therapeutics. Many small-molecule inhibitors have demonstrated an ability to treat or prevent inflammatory diseases implicated by TNF-α (for a review see Lowe, 1998 Exp. Opin. Ther. Patents 8:1309-1332). In addition, pharmaceutical compounds that can stimulate the activity or increase the production of certain cytokines, including IL-10, and immune response factors such as T-cells, may be beneficial therapeutics.
Thalidomide is an emerging immunotherapeutic agent and, in addition to utility in treating a variety of inflammatory disorders, it is projected to be useful in treating cancers (see e.g., Marriott et al., 1999, Immunology Today 20:537-540). Thalidomide has been shown to inhibit production of both TNF-α and IL-1β while simultaneously increasing the production of IL-10 and T-cells, and has been tested against a variety of autoimmune and inflammatory diseases, see e.g., Gutierrez-Rodriguez, 1984, Arth. and Rheum 27:1118; The Physician's Desk Reference, 54th edition, 911-916, Medical Economics Company (2000). Thalidomide's teratogenic properties, however, have limited its use and driven efforts to discover analogs or derivatives with reduced toxicity and improved therapeutic activity. The design of thalidomide analogs and derivatives attempts to maintain/enhance activity while subverting toxicity (for a discussion of some recent advances in TNF-α inhibitors structurally related to thalidomide see Marriott, 1997, Exp. Opin. Invest. Drugs 6:1105-1108). For example, the following references have disclosed alternatives to thalidomide as inhibitors of TNF-α production: U.S. Pat. Nos. 5,385,901; 5,635,517; and 5,798,368 and PCT International Application WO 98/54170. Despite these disclosures, there remains a need for non-toxic and high-potency compounds that treat or prevent cancer, inflammatory disorders, and autoimmune diseases.
Citation or identification of any reference in Section 3 of this application is not an admission that such reference is available as prior art to the present invention.